Using ElasticSearch and Kibana for Business Intelligence
We have the same needs.Tools like Qlik, PowerBI, Tableau require to increase the overall insfrastructure stack and where you are designin solution to bring abroad without the possibility to share anyting they could be not the best possible option in terms of both costs & complexity.
I have used devextreme by devexpress. Its server side approach using custom store is very efficient to handle & perform operations on large amount of data. In case of mysql and mssql db, I have myself performed grouping, sorting ,filtering, summaries on 10 million data using devextreme.